JP2017110638A - Application system supply pump for liquid coating products - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump for supplying an application system of a liquid covering product.SOLUTION: A pump (1) for supplying an application system of a liquid covering product, includes a motor (3) for driving at least two pistons, and a drum (9) rotated by the motor and including an outer peripheral cylindrical surface (90) having a cam profile (92). Each piston is secured to a rod (51, 61) on which a roller (53, 63) is fastened while rolling over the cam profile such that the roller connected to the piston via one of the rods is translated along a translation axis (X-X') of the corresponding piston under the action of rotation of the drum. Each roller is kept into contact with the cam profile in an angular offset position to a position of the other roller, one of the pistons moves when the other piston reaches an inversion point of its movement. The pump includes compensating means (10) suitable for accelerating one of the pistons.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pump for supplying an application system for a liquid coating product.

  Application system supply pumps for liquid coating products such as paint are typically made up of an electric or pneumatic motor, a hydraulic pump, and a coupling means connecting the motor and the pump. An electric pump refers to a supply pump having an electric motor and a hydraulic pump that is a pump having a hydraulic motor. Preferably, electric pumps are used because of their better performance and lower cost of use. The problem is to convert the motion between an electric motor with rotational motion and a hydraulic pump with reciprocating linear motion. When the direction of motion is reversed, the hydraulic pump piston reaches zero speed, which results in a pressure drop at the pump outlet. Therefore, an electric pump must be provided to make up for these inversions.

  Pumps comprising a single piston driven by a connecting rod-crank system are known. In these pumps, the rotational speed of the electric motor is controlled to obtain a constant flow rate. A pump comprising a single piston driven by a rack is known from US Patent Application Publication No. A2015 / 219819. Inversion is done on the different teeth of the rack to reduce its wear. None of these systems make it possible to prevent a pressure drop at the outlet of the pump.

  It is also known to use two diametrically opposed pistons, i.e. pumps with a phase difference of Piradian, their movement being brought about by the rotation of a heart-shaped cam, their profile and associated mechanism being 1 During the reversal of the movement of one piston, the other piston is configured not to be completely at the end of its travel distance. However, such a system is not completely satisfactory because it involves a continuous change in the torque to be applied by the motor. Furthermore, given the known heart-shaped cam design, the latter has only one means for pushing the piston of the hydraulic pump. Thus, a return mechanism is required to achieve movement of the piston in the opposite direction.

  The present invention aims to overcome these drawbacks by proposing a novel pump for supplying a liquid coating product application system and provides a more effective correction of pump piston reversal.

  To achieve that object, the present invention relates to a pump for supplying an application system for a liquid coating product, which includes a motor for driving at least two pistons. The pump is rotated by a motor and includes a drum including an outer cylindrical surface having a cam profile, each of the pistons being fixed to a rod mounted with a roller rotating over the cam profile, A roller connected to each of the pistons through one of them is translated along the translation axis of the associated piston under the rotational action of the drum, each of the rollers being angular with respect to the piston of the other roller. Is in contact with the cam profile at the offset position, one piston is moving when the other piston reaches the reversal position of the movement direction, and another piston is moving in its movement direction. It comprises correction means suitable for accelerating one of the pistons when the reversal point is reached.

  Thanks to the present invention, the acceleration of one piston provides an effective correction of the pressure drop during the reversal of another piston. The pressure obtained at the pump outlet is generally constant.

  According to an optional but optional aspect of the present invention, such a pump can include one or more of the following features, considered in any technically acceptable combination.

  The correction means includes means for accelerating the rotational speed of the drum for a predetermined length of time before and after the passage of one of the pistons near its reversal point. In this embodiment, during reversal, the rotational speed of the motor increases while the torque decreases and the power required from the motor remains constant.

  The acceleration means includes a motor control unit.

  The correction means includes a pressure sensor located downstream from the piston, and the acceleration means is suitable for increasing the rotational speed of the drum as a function of the pressure value measured by the pressure sensor.

  A correction means is formed by the two angular sectors of the cam profile having a tilt angle with respect to a plane perpendicular to the axis of rotation of the drum that is greater than the tilt angle of the remaining angular sectors of the cam profile. In this embodiment, correction is performed while maintaining a constant speed and motor torque.

  The inclination angle of the angular sector of the cam profile forming the correction means is twice the inclination angle of the remaining angular sector of the cam profile.

  The pump includes two pistons that are angularly offset by 90 °.

  The cam profile includes two helical slots, each extending over half the circumference of the drum and symmetric with respect to a plane passing through the axis of rotation of the drum.

  The rollers are angularly offset at an angle comprised between 70 ° and 100 °.

  The offset angle of the roller is 90 °.

  In view of the following description of a feed pump according to its principles, provided as a non-limiting example in connection with the accompanying drawings, the invention will be better understood and other advantages of the invention will emerge more clearly .

1 is a perspective view of a pump according to a first embodiment of the present invention. FIG. 2 is an enlarged view of detail II in FIG. 1. FIG. 3 is a top view of the pump of FIGS. 1 and 2. FIG. 4 is a cross-sectional view taken along plane IV-IV in FIG. 3. 5 is a curve showing the change in rotational speed as a function of the angular position of the motor of the pump of FIGS. It is the figure which expanded the pump which concerns on 2nd Embodiment of this invention similar to FIG. 4, and shows only the drum and roller of a pump. It is a figure similar to FIG. 1 of the pump which concerns on 3rd Embodiment of this invention.

  1 to 5 show a pump for supplying an application system for a liquid coating product (not shown). The pump 1 includes an electric motor 3 that also has a rotational axis X-X '.

  The motor drives two pistons 5 and 6 respectively mounted in a chamber 8 that can slide along respective axes X5 and X6 parallel to axis X-X '. The movement of the pistons 5 and 6 in the chamber 8 makes it possible to carry pressurized liquid coating products such as paint.

  The motor 3 drives the pistons 5 and 6 through a transmission system that includes a drum 9 that is rotated by the motor 3 about an axis X-X '. The transmission of rotation from the motor 3 to the drum 9 can be direct or indirect through a reducer system not shown.

  The drum 9 includes an outer peripheral cylindrical surface 90 centered on the axis X-X ′. The outer peripheral surface 90 has a cam profile 92. The pistons 5 and 6 are respectively fixed to the first rod 51 and the second rod to which the first roller 53 and the second roller 63 are attached. The rollers 53 and 63 rotate on the cam profile 92 and the rod 51 The rollers 53 and 63, which are connected to the pistons 5 and 6 through 61 and 61, respectively, translate in parallel with the axis XX ′ under the rotating action of the drum 9.

  In the example shown, the cam profile 92 extends over half the circumference of the drum 9 and is symmetrical with respect to a plane P1 passing through the drum rotation axis XX ′ and Formed by a continuous slot containing 95. Slots 94 and 95 include respective cylindrical bottoms 94a and 95a, upper helical walls 94b and 95b, and lower helical walls 94c and 95c, respectively. Rollers 53 and 63 selectively contact one of the upper 94b and 95b or lower 94c and 95c helical walls along a contact line perpendicular to axis X-X '.

  In FIG. 4, the motor 3, the drum 9, and the rollers 53 and 63 appear double because of the arrangement of the cut surfaces IV-IV.

  When the drum 9 rotates on itself about the axis XX ′, the contact between the helical walls 94b, 95b, 94c, 95c and the rollers 53 and 63 results in translational movement of the rods 51 and 61, which 5 and 6, thereby making it possible to alternatively obtain a suction of the coated product and then its pressurized discharge at the outlet of the pump 1.

  Each of the pistons 5 and 6 has a top dead center and a bottom dead center corresponding to the reversal point of the translational movement direction. During these reversals, the linear speed of the pistons 5 and 6 decreases and then passes a zero value, which causes a cut-in pressure at the pump outlet. It is therefore necessary to make up for the speed reduction of one of the pistons 5 and 6 when it reaches its reversal point with the movement of another piston. Therefore, according to the present invention, one contact point of the rollers 53 and 63 with the cam profile 92 is at an angularly offset position relative to the position of the contact point of the other roller, and one piston 5 And 6 are moving when the other piston is at the reversal of its direction of motion. Advantageously, the positioning of each of the rollers 53 and 63 allows the roller 53 to reach its upper inversion point, as shown in FIG. 4, while the roller 63 is approximately intermediate through its upward movement. It is in. This makes it possible to partially compensate for the pressure drop due to piston reversal.

  The offset angle A of the rollers 53 and 63 is preferably comprised between 70 ° and 100 °. Preferably, the offset angle A of the roller is 90 °. This angle A is also the angle formed by the axes X5 and X6 with respect to the axis X-X '. Since the pistons 5 and 6 reach their reversal points at the same time and cannot make up for each other, the offset is never 180 °.

  Thus, as shown in FIG. 3, rollers 53 and 63 are offset by a quarter rotation of drum 9, which means that roller 53 reaches the boundary between slots 94 and 95, while roller 63 is This means that the center of the slot 95 corresponding to half of the moving distance of the piston 6 has been reached.

  In order to more effectively correct the reversal of the piston, according to the present invention, the pump 1 is adapted to accelerate one of the pistons 5 and 6 when the other piston reaches its reversal point. Including means.

  According to the first embodiment of the present invention, the correction means is shown schematically in FIG. 1 during a predetermined length of time before and after one of the pistons 5 and 6 passes, near its reversal point. Means for accelerating the rotational speed of the drum 9 formed by the control unit 10 shown. Thus, during the entire period when one of the pistons decelerates, passes through zero speed and then accelerates again, the rotational speed of the drum 9 is accelerated by the control unit 10 and the translational speed of the other piston is again Accelerate and give correction for deceleration of the first piston. This method is illustrated by the curve illustrated in FIG. 5, which shows the increase in the rotational speed V of the drum 9 as a function of the angular position of the drum 9. The speed profile is sent to the motor 3 by the control unit 10 in the form of an electrical signal S10. With each quarter rotation of the drum 9 corresponding to a half-piradian rotation, a reversal of the piston 5 or 6 takes place, whereby a correction is provided by an increase in the speed V around this angular position.

  As an example, the rotational speed of the drum 9 can be increased from 5 revolutions / minute to 10 revolutions / minute.

  The control unit 10 is preferably an electronic unit that performs an enslaved control of the rotational speed of the motor 3.

  As an example, the angular spacing before and after the piston passes near the reversal point where the speed of the drum 9 increases can be comprised between 0.14 radians and 0.28 radians.

  A second embodiment of the invention is shown in FIG. In this embodiment, the members shared with the first embodiment have the same reference numbers and operate in the same way. Only differences from the first embodiment will be described below.

  In FIG. 6, only the drum 9 and the rollers 53 and 63 at that two positions in the cross-sectional view of FIG. 4 are shown with concerns about clarity.

  In the embodiment shown in FIG. 6, the correction means can include two angular sectors 97 of the cam profile 92 to replace or concomitant with the means for accelerating the rotational speed of the drum 6, and the rotational axis XX The tilt angle A97 measured with respect to the plane P2 perpendicular to 'is greater than the tilt angle A92 of the remaining angular sector of the cam profile 92 (referred to as nominal). The remaining angular sector is defined as part of the cam profile 92 that extends outside the angular sector 97. An angular sector 97 with an enhanced slope is located at the center of each of the slots 94 and 95. Thus, since rollers 53 and 63 are offset by 90 °, roller 53 reaches the reversal point as shown on the left side of FIG. 6, while roller 63 is angular sector 97 as shown on the right side of FIG. Contact with. Therefore, the translational movement speed along the axis X-X ′ of the roller 63 increases in this way as the inclination of the walls 94b, 95b, 94c and 95c increases. Therefore, the acceleration of the piston 6 fixed to the roller 63 compensates for the deceleration of the piston 5 and the passage of zero speed. This allows the fact that one of the pistons 5 and 6 has reached its reversal point to produce only a relatively small change in the outlet pressure of the pump 1.

  According to one optional but optional aspect of the present invention, the value of the tilt angle A97 is preferably twice the value of the tilt angle A92.

  Of course, the position of the angular sector 97 in the center of the slots 94 to 95 is related to the direction of the rollers 53 and 63 at 90 °.

  According to the third embodiment, the pump 1 can also include a pressure sensor 100 located downstream of the two hydraulic outlet conduits C1 and C2 of the pistons 5 and 6, and measures the pressure at the outlet of the pump 1. And measuring the pressure drop following the approach to one reversal point of the piston. The pressure sensor 100 included in the correction means is connected to the pressure unit 10 or the rotation of the drum 9 as a function of the pressure value measured by the pressure sensor 10 and sent to the control unit 10 in the form of an electrical signal SP. Connected to any other means suitable for increasing speed. To achieve that goal, the start of acceleration of the speed of the drum 9 may be passed near the outlet pressure value below the threshold value (e.g. equal to 15 bars).

  According to one embodiment of the invention not shown, the pump 1 can include more than two pistons.

  The features of the embodiments and alternatives described above can be combined to form new embodiments of the invention.

Claims (10)

  A pump (1) for supplying a liquid coating product application system comprising a motor (3) for driving at least two pistons (5, 6), the cam profile (92) being rotated by said motor (3) A drum (9) including an outer cylindrical surface (90) having a rod (51,), each of the pistons mounted with a roller (53, 63) rotating over the cam profile (92). 61) and the rollers connected to each of the pistons through one of the rods, under the rotational action of the drum (9), are associated with the translation axes (5, 6) of the piston (5, 6). XX ′), each of the rollers being moved into the cam profile at a position (A) that is angularly offset with respect to the position of the other roller. Touching, one piston (6) is moving when the other piston (5) reaches the reversal of the direction of motion and another piston (5, 6) is moving Pump (1), comprising correction means (97; 10; 100) suitable for accelerating one of said pistons (5, 6) when a direction reversal point is reached.   Means for accelerating the rotational speed of the drum (9) during a predetermined length of time before and after one of the pistons (5, 6) passes near the reversal point The pump according to claim 1, comprising (10).   3. Pump according to claim 2, characterized in that the acceleration means comprise a control unit (10) of the motor (3).   The correction means includes a pressure sensor (100) located downstream from the piston (5, 6), and the acceleration means (10) is a function of the pressure value (SP) measured by the pressure sensor (100). A pump according to claim 2 or 3, characterized in that it is suitable for increasing the rotational speed (V) of the drum (9).   The correction means has an inclination angle (P2) with respect to a plane (P2) perpendicular to the rotation axis (XX ′) of the drum (9), which is larger than the inclination angle (A92) of the remaining angular sector of the cam profile (92). Pump according to claim 1, characterized in that it is formed by two angular sectors (97) of the cam profile (92) with A97).   The inclination angle (A97) of the angular sector (97) of the cam profile (92) forming the correction means is twice the inclination angle (A92) of the remaining angular sector of the cam profile (92). The pump according to claim 5, wherein   Pump according to any one of the preceding claims, characterized in that it comprises two pistons (5, 6) angularly offset by 90 °.   The cam profile (92) is symmetrical with respect to a plane (P1), each extending over half the circumference of the drum (9) and passing through the rotation axis (XX ′) of the drum; 8. A pump according to any one of the preceding claims, characterized in that it comprises two helical slots (94, 95).   9. Pump according to any one of the preceding claims, characterized in that the rollers (53, 63) are angularly offset by an angle (A) comprised between 70 [deg.] And 100 [deg.]. .   Pump according to any one of the preceding claims, characterized in that the offset angle (A) of the rollers (53, 63) is 90 °.

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